"Breeding-back" aims to restore or immitate extinct animals by selective breeding. This blog provides general information, the facts behind myths and news from various projects.

Saturday, 19 August 2017

Setting milestones for "breeding-back"

Now, in
2017, there are many different aurochs projects (Taurus cattle, Tauros Project,
Uruz Project, Auerrind Project) and Heck cattle is still a very heterogeneous
pool but slowly increasing in quality. More and more nature areas become free
for natural grazing by large herbivores and the numbers of aurochs-like cattle
is rising with each year. So it is maybe time to speak about the milestones of "breeding-back". What is the goal, and when can we consider it achieved?

In my previous
post I explained why I think selective breeding with domestic cattle cannot
deliver something that is a true aurochs in the strict sense of the word, but
at least something that comes morphologically, ecologically and behaviourally
very close. The ideal state is having these cattle living independently in the
wild as wild animals, and successively having their genome shaped by nature.
This is the final goal and it will take its time until it is reached. But I
think there are several milestones for “breeding-back” that I want to outline
here.

1. Creating a population that contains all
achievable aurochs-like traits

Prior to
“breeding-back”, there was no population of modern cattle in which all
achievable aurochs-like traits were found. That is why “breeding-back”, no
matter which project, has to rely on crossbreeding a set of breeds in which
each breed contributes one or more desired traits (be it morphologic, ecologic
et cetera). By doing so, you create a heterogeneous cross population that also
contains a lot of undesired traits. It is the goal of selective breeding to get
rid of those undesired traits, but before you can do that, all aurochs-like
traits have to be present in the population in order to achieve a result that
is as authentic as possible. We probably cannot achieve 100% perfect copy of
the aurochs working with modern domestic cattle (for details, see here), but
something that is very close in many aspects. That is why I speak of allachievable
aurochs-like traits instead of all
aurochs-like traits.

Taurus
cattle, both the population at the Lippeaue and Hortobagy, have achieved this
milestone. You can find all the desired achievable traits (accurate colour, body
size, horn size, horn curvature, sufficient body shape, sufficient snout length,
sufficient sexual dimorphism [more on that in a future post]) in both
populations respectively. To give an example, forwards-facing horns are
prevalent in the Lippeaue herd. Inwards-facing horn tips are present, but only
a few individuals. Selective breeding has to fixate this trait in the
population, and therefore get rid of the individuals with insufficient horn
curvature. The same with snout length: some cows and bulls show an aurochs-like
long snout, the challenge is to fixate it in the population.

As for the
Tauros Project and the Auerrind Project, it might be too early to judge yet. For
the Tauros Project, I fear that they will need some boost in horn volume and
body size (for the latter, there is no data, however). The breed choice of the
Auerrind Project should contain most of the achievable aurochs-like traits, the
crossbreeds that will be born in the future will show how well traits such as
sexual dichromatism and inwards-curving will work out horns work out. For the
Uruz Project, there are no publicly known cross herds for now, so that I cannot
say much yet.

2. Uniting all achievable traits in one
individual

The next
milestone would be to unite all the aurochs-like traits that are present in the
population in one animal at least. This is a milestone that has not been
reached yet. Of course the judgement is also a bit open to one’s preferences,
as we cannot directly compare the individuals to living aurochs. For example, I
think that the Taurus bull Lamarck and the Taurus cow Lisette are rather close
to the goal already. But Lamarck’s horns could be more curved, the snout
longer, the body still more athletic and probably also the legs slightly
longer. And maybe I am picky, but I think Lamarck would also need more frizzy and curled forelocks in order to achieve "perfection" regarding aurochs-likeness. Lisette looked great overall, but her horns could have been larger and
more curved, she was small overall and had white spots on the belly (how much
does that matter? More on that in a future post). My choice of those two
individuals as examples for very aurochs-like cattle is more or less subjective; there are many good individuals, also of
pure breeds. Many Corriente and Lidia are rather close to what I consider the
achievable maximum, but with noticable deficiencies (in those two breeds it is
primarily the lack of body size, for example).

So we still
need a bit patience and luck until the first individual that really displays a
maximum of aurochs-resemblance that is possible. Furthermore, there will
probably be no universal agreement on what actually is a perfect maximum of achievable
aurochs-likeness. Different people also have different priorities.

3. Getting rid of the undesired traits and
create a stable population

When the
first universally satisfying animals are born, the next challenge of selective
breeding is to fixate this genetic make-up in the whole population. That means
to finally exterminate the last undesired traits and create a truly
homogeneous, aurochs-like population.

Cattle are
a slowly reproducing species, and therefore it will take its time, probably
several decades, until number 3 is achieved – especially since some projects,
such as the Auerrind Project, have just started yet, and the Tauros Project is
in the beginning phase as well. Some methods have been discussed on the web to
speed up the process, including breeding schemes based on “true Filial
crosses”, but it is important to maintain a certain amount of genetic diversity
at the same time, as this is crucial for the populations health and
adaptability.

4. Releasing the animals and letting them
evolve into a wild animal

Cattle that
live and reproduce independently under natural circumstances without the need
of veterinary care and supplementary feeding are the goal of all of the
projects anyway, as they mostly serve a conservational purpose with the cattle
as grazing tools. And for “breeding-back”, the goal of maximum authenticity has
to be a truly wild animal at some point, as the aurochs itself was a wild
animal per definition. That’s why I wrote

“If ‘breeding back’ aims to approach the
aurochs as closely as possible, the result has, ultimately, to be a wild animal.”

in 2015. Phenotypical
plasticity and natural selection will alter the anatomy, physiology, behaviour,
genetics and ecology of the aurochs-like cattle, and chances are good that this
will make them even more aurochs-like (see the Dedomestication Series), and
after a sufficient amount of time the population can be considered feral, and
after that, truly wild. But it will take a very long time, probably centuries,
until the selective pressure has altered the genetics of the population enough
to speak of a truly wild animal. Nevertheless, we will probably live long
enough to see those cattle looking and behaving like wild animals, and they
will be suited to their environment.

Especially
because the process of dedomestication can run parallel to “breeding-back”. Actually,
the cattle of all those projects live in a more or less semi-feral state
already in the grazing projects they are used. However, the breeding is still (and
has to be) strongly regulated by choosing one breeding bull per herd plus
selection. The next step would to let them breed naturally when they reached a
satisfying level of aurochs-resemblance (with the competition of several bulls
for breeding rights), and influence the population only by the removal of
individuals that display too many undesired traits (however, I think this could
be a mistake at too early phase, I can explain why). And in the long run, the
population can reproduce freely and develop into a wild animal and artificial
selection is done only on traits that would otherwise remain in the population
for a very long time, such as recessive traits or domestic colour variants.

This is
basically the plan that the Tauros Project has presented:

Although I
do not think it is realistic that natural selection has enough time to turn the
population into truly wild animals by 2025 or any point of this century, most
of us will probably live long enough to populations of very aurochs-like cattle
living freely and independently and behaving and looking like wild animals.

5. Numerous populations of aurochs-like cattle
living in nature areas on the complete Holocene range of the European aurochs

Of course
it is one of the goals to reintroduce cattle not only in one or two single
reserves, but restore the ecological niche of the aurochs in as many reserves
as possible on its former range. Actually, this milestone can be considered
reached or almost reached already, just not with the desired very aurochs-like,
stable and more or less dedomesticated cattle that are the goal, but the current
“breeding-back” cattle that we have. There are “breeding-back” herds in nature
reserves in virtually all regions of the European continent, from the Iberian
peninsular to the Balkans, from the Netherlands to Latvia.

And once
all those herds have reached the four previous milestones, we can confidently
say that the niche of the aurochs has been filled as best as possible with
domestic cattle until a true revival of the aurochs via genetic methods is
feasible and executed (cloning or CRISPR-Cas9).

This is at least the way I would draw a scheme for the stepwise progress of "breeding-back", but I think that many people might see it in a similar way.

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About this blog

This blog is on everything related to the so-called “breeding-back” of extinct animals: From the extinct animals themselves, over their often domestic descendants and dedomestication to news and facts about various breeding-back projects, reports and photos from my own breeding-back related trips. I try to have a balanced and fact-based approach to this subject and to dismantle many of the popular myths. Enjoy!

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About me

My major interest always have been extinct animals, from dinosaurs to Pleistocene megafauna and more recent extinctions. Besides that I am interested in evolution, genetics and ecology.
I am also an amateur animal artist, making drawings and models mostly of extinct animals.